In a manufacturing process of a semiconductor device or a flat panel display (FPD) such as a liquid crystal display (LCD), there is known a plasma processing apparatus for performing a plasma process on various kinds of substrates such as a glass substrate. The plasma processing apparatus may be classified into a capacitively coupled plasma processing apparatus and an inductively coupled plasma processing apparatus according to a method for generating plasma.
Known as a typical example of such a capacitively coupled plasma processing apparatus (hereinafter, simply referred to as a “CCP processing apparatus”) is an apparatus in which two sheets of electrode plates are provided within a processing chamber and one of the two electrode plates is connected with a high frequency power supply while the other is grounded. By way of example, in such a CCP processing apparatus, an electric field is generated between the electrode plates by applying a high frequency power to the one of the electrode plates from the high frequency power supply. As a result, electrons are generated in a processing space between the electrode plates. The electrons are accelerated by the electric field generated by the high frequency power and collide with molecules of a processing gas, so that capacitively coupled plasma is generated. Accordingly, a plasma process is performed on a substrate by using the plasma.
In the CCP processing apparatus, since plasma in a peripheral region of the chamber is diffused, a plasma density in the peripheral region of the chamber is decreased. Thus, a plasma density in a central region of the chamber tends to be higher than that in the peripheral region thereof. Accordingly, a plasma density within the chamber may become non-uniform and there is a problem that it may not be possible to perform a uniform plasma process on the substrate.
To solve the problem, there has been proposed a plasma processing apparatus including an electrode plate provided with a hollow cathode structure within a processing chamber (see, for example, Patent Document 1). By using the hollow cathode structure, it has been attempted to uniformize plasma distribution within the processing chamber and perform a uniform plasma process on a substrate.    Patent Document 1: Japanese Patent Laid-open Publication No. 2003-068716
However, even in the plasma processing apparatus having the hollow cathode structure formed in the processing chamber, a density or a distribution range of the generated plasma mainly depends on a shape of the hollow cathode structure, e.g., a size and a depth of grooves or hole. Thus, it may be still difficult to control the plasma density in the processing chamber to a desired state.